Plasma reactor

ABSTRACT

A method of making carbon black. Such method is described including generating a plasma by subjecting a plasma gas to a plasma arc, mixing a feedstock material with the plasma gas and combining the mixture in a reactor at a given reactor temperature to produce carbon black, wherein the feedstock is mixed with the plasma gas outside of the area occupied by the plasma arc. The carbon black produced by such process is also described.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. application Ser. No.14/601,793 filed Jan. 21, 2105, which claims the benefit under 35 U.S.C.§119(e) of U.S. Provisional Application No. 61/934,207 filed Jan. 31,2014, the disclosures of which are expressly incorporated by referenceherein in their entireties.

TECHNICAL FIELD

The field of art to which this invention generally pertains is methodsand apparatus for making use of electrical energy to effect chemicalchanges.

BACKGROUND

There are many processes that can be used and have been used over theyears to produce carbon black. The energy sources used to produce suchcarbon blacks over the years have, in large part, been closely connectedto the raw materials used to convert hydrocarbon containing materialsinto carbon black. Residual refinery oils and natural gas have long beena resource for the production of carbon black. Energy sources haveevolved over time in chemical processes such as carbon black productionfrom simple flame, to oil furnace, to plasma, to name a few. As in allmanufacturing, there is a constant search for more efficient andeffective ways to produce such products. Varying flow rates and otherconditions of energy sources, varying flow rates and other conditions ofraw materials, increasing speed of production, increasing yields,reducing manufacturing equipment wear characteristics, etc. have allbeen, and continue to be, part of this search over the years.

The systems described herein meet the challenges described above, andadditionally attain more efficient and effective manufacturing process.

BRIEF SUMMARY

A method of making carbon black is described including generating aplasma by subjecting a plasma gas to a plasma arc, mixing a feedstockmaterial with the plasma gas and combining the mixture in a reactor at agiven reactor temperature to produce carbon black, wherein the feedstockis mixed with the plasma gas outside of the area occupied by the plasmaarc.

Additional embodiments include: the method described above where thefeedstock is natural gas; the method described above where the naturalgas and plasma are mixed at a high intensity; the method described abovewhere the mixing is turbulent; the method described above resulting insubstantial elimination of torch fouling; the method described aboveresulting in the production of high quality carbon black, having moreuniform time temperature carbon black production history, higher surfacearea per degree of reactor temperature, higher surface area per specificenergy input, higher product structure, higher tinting strength, reducedproduct grit, and reduced product extract; the method described abovewhere the feedstock is injected so as to fully form the carbon blackproduct prior to contact with any solid surface present in the reactor;the method described above where increasing the reactor temperaturereduces the required time for the carbon black product to fully form;the method described above where the carbon black product produced isquenched after sufficient residence time in the reactor so as to reduceproduct extract levels; the carbon black product produced by theprocesses described above.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic representation of a system as described herein.

FIGS. 2 and 3 show schematic representations of gas non-recirculationand recirculation as described herein.

DETAILED DESCRIPTION

The particulars shown herein are by way of example and for purposes ofillustrative discussion of the various embodiments of the presentinvention only and are presented in the cause of providing what isbelieved to be the most useful and readily understood description of theprinciples and conceptual aspects of the invention. In this regard, noattempt is made to show details of the invention in more detail than isnecessary for a fundamental understanding of the invention, thedescription making apparent to those skilled in the art how the severalforms of the invention may be embodied in practice.

The present invention will now be described by reference to moredetailed embodiments. This invention may, however, be embodied indifferent forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those skilled in the art.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. The terminology used in thedescription of the invention herein is for describing particularembodiments only and is not intended to be limiting of the invention. Asused in the description of the invention and the appended claims, thesingular forms “a,” “an,” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise. Allpublications, patent applications, patents, and other referencesmentioned herein are expressly incorporated by reference in theirentirety.

Unless otherwise indicated, all numbers expressing quantities ofingredients, reaction conditions, and so forth used in the specificationand claims are to be understood as being modified in all instances bythe term “about.” Accordingly, unless indicated to the contrary, thenumerical parameters set forth in the following specification andattached claims are approximations that may vary depending upon thedesired properties sought to be obtained by the present invention. Atthe very least, and not as an attempt to limit the application of thedoctrine of equivalents to the scope of the claims, each numericalparameter should be construed in light of the number of significantdigits and ordinary rounding approaches.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the invention are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. Any numerical value, however, inherently contains certainerrors necessarily resulting from the standard deviation found in theirrespective testing measurements. Every numerical range given throughoutthis specification will include every narrower numerical range thatfalls within such broader numerical range, as if such narrower numericalranges were all expressly written herein.

Additional advantages of the invention will be set forth in part in thedescription which follows, and in part will be obvious from thedescription, or may be learned by practice of the invention. It is to beunderstood that both the foregoing general description and the followingdetailed description are exemplary and explanatory only and are notrestrictive of the invention, as claimed.

As described herein, controlling the design parameters of a plasmareactor as described below results in the production of high qualitycarbon blacks having the properties described herein. Prevention offeedstock or formed product entering the plasma arc prevents fouling ofthe torch and enables a more uniform time temperature history of thefeedstock/product. Intense mixing of, for example, natural gas feedstockand plasma gases can maximize surface area, tint and structure as wellas minimizing extract for a given reactor temperature and reduce thetemperature variation the product forms in. Sufficient time of flightfrom feedstock injection to solid surface contact so as to fully formthe product prior to contact with the solid surface results in theimproved properties described herein. This will require longer timeswhen operating at lower temperatures and/or less intense mixing. Andsufficient residence time prior to quenching reduces product extractlevels to those required by the market.

There are clearly benefits of separating the plasma arc from thefeedstock. Previous methods of using a plasma to make carbon blackproducts have not recognized the link intense mixing has to the productquality recognized herein and especially the benefits of turbulentmixing rather than laminar or transitional mixing. Mixing willdefinitely impact surface area, but will also impact the structure,tinting strength, and extract levels, among other things. Similarly,linking time of flight from feedstock injection to the wall has asignificant impact on product grit and reactor fouling. Othersignificant benefits include, reducing the time of flight required byimproving the mixing, how increased reactor temperature reduces therequired time of flight, linking residence time at temperature withproduct extract levels, and reducing the extract level by improving themixing.

The processes as described herein also overcome generated products thatsuffered from one or more of the following: low surface area vs reactortemperature, and hence low surface area for a specific energy input; lowproduct structure even when not using any structure control additives,high product grit, and high product extract.

EXAMPLE 1

In FIG. 1, the plasma torch (11) is shown generating an arc (12) in theplasma torch chamber (15). The use of a restriction (17) between theplasma torch chamber and the reactor chamber (16) helps prevent anyfeedstock or carbon black getting back to the plasma arc where it coulddecompose, crack and/or and foul the torch. The recirculation (13) helpskeep the forming carbon black particles (14) more towards the middle ofthe chamber away from the walls. The restriction also accelerates thefluid to create turbulent mixing conditions, which reduces the timetaken to heat the feedstock, resulting in a more uniform timetemperature history. This faster mixing also increases the surface area,structure, and tint, and reduces the time to form the black and soreduces the grit and extract as well as coke deposits and other foulingon the reactor walls. By producing higher surface area at the samereactor temperature, the energy required per amount of product for agiven surface area is minimized. The expansion from the restrictioncreates recirculation, keeping the forming product away from the wallsof the reactor while also minimizing the reactor's surface area for agiven volume/residence time, which minimizes heat losses as well.

EXAMPLE 2

In FIG. 2, insufficient recirculation occurs. The bulk of the flow ofplasma gases (22) remains attached to the wall (20), i.e. follows thewall. The injection of feedstock such as natural gas, oil, etc. (21)results in a wake (23) that sucks a portion of the feedstock onto thewall where it will form coke (24) that may plug the restriction and/orincrease the grit level in the product (most grit being coke).Conversely, in FIG. 3 the larger angle of expansion in the wall (30)results in the flow of plasma gasses (32) detaching from the wall (30)creating recirculation (34). The recirculated gases (34) from thereactor, that contain fully formed product, then counter the tendency ofthe wake (33) of the injected natural gas or oil (31) to suck some ofthe natural gas/oil towards the wall (33). This would also favor placingthe feedstock injection point somewhat close to the end of therestriction between the plasma chamber and the reactor so that therecirculated gasses and fully formed black (34) essentially fill thewake of the injected feedstock (33).

Thus, the scope of the invention shall include all modifications andvariations that may fall within the scope of the attached claims. Otherembodiments of the invention will be apparent to those skilled in theart from consideration of the specification and practice of theinvention disclosed herein. It is intended that the specification andexamples be considered as exemplary only, with a true scope and spiritof the invention being indicated by the following claims.

What is claimed is:
 1. A method of making carbon black comprisinggenerating a torch plasma by subjecting a plasma gas to a plasma arc,mixing a feedstock material with the plasma gas and combining themixture in a reactor at a given reactor temperature to produce carbonblack, wherein the feedstock is mixed with the plasma gas outside of thearea occupied by the plasma arc.
 2. The method of claim 1, wherein thefeedstock is natural gas.
 3. The method of claim 2 wherein the naturalgas and plasma are mixed at a high intensity.
 4. The method of claim 3wherein the mixing is turbulent.
 5. The method of claim 1 resulting insubstantial elimination of torch fouling.
 6. The method of claim 1resulting in the production of high quality carbon black, having moreuniform time temperature carbon black production history, higher surfacearea per degree of reactor temperature, higher surface area per specificenergy input, higher product structure, higher tinting strength, reducedproduct grit, and reduced product extract.
 7. The method of claim 1wherein the feedstock is injected so as to fully form the carbon blackproduct prior to contact with any solid surface present in the reactor.8. The method of claims 3 wherein the high intensity mixing region isexpanded after feedstock injection to detatch flow from the wall so asto create recirculation of fully formed carbon black product and keepthe forming product off the wall of the reactor.
 9. The method of claim8 wherein the recirculation counteracts the wake generated by injectingthe feedstock to prevent the wake from causing the feedstock to contactthe wall prior to fully forming the product.
 10. The method of claim 9wherein increasing the reactor temperature reduces the required time forthe carbon black product to fully form.
 11. The method of claim 1wherein the carbon black product produced is quenched after sufficientresidence time in the reactor so as to reduce product extract levels.12. The carbon black product produced by the process of claim 1.